Sunday, October 31, 2010

My grocery store sells generic versions of bottled water, soap, breakfast cereal, butter, milk and mobile voice/Internet service. Now thats quite remarkable considering Rewe, the German grocery store chain I am alluding to, doesn't really have a history in the German telecommunications market. What they do have are 15445 stores across Europe that can stock up prepaid SIM cards branded "ja! Mobil" (the name comes from their generic in-store brand). Their physical presence and the mind space ja! occupies drives their business model. If shoppers can drink ja! branded generic cola then they could as well use ja!-branded mobile voice/Internet service.

The innovation here is the marketing possibility offered by Rewe grocery stores (instead of any technical innovation). Rewe has partnered with T-Mobile in Germany to implement its ja! branded "mobile operator". T-Mobile provides a white-label technical platform and Rewe simply brands it "ja! mobile". T-Mobile wins because it gets to sell its service at a discount to lower-paying market segments without putting off the premium T-Mobile customers, Rewe makes a neat profit by leveraging the ja! brand, and the customer wins by getting a discounted service from the best mobile operator of Germany, minus the T-Mobile brand.

I was looking at ja! mobile pricing. There are various flavors of pre-paid and flat-rate plans, although the focus seems to be on pre-paid plans that require no long-term contract and can be dispensed at Rewe's check-out counters. Depending on a customer's typical usage, s/he can can trade-off get a discounted subset of services from among the services offered - SMS, MMS, in-network calling, fixed-line calls, data etc. Interestingly, customer support is not free. Its a little like the contemporary airline business where everything from customer service to carry-on baggage can become a chargeable add-on rather than part of the product. Customers need to be mindful of what their money is buying them before assuming that things like customer service or technical support is part of the product.

Brick-and-mortar stores also sell iTunes gift cards and Facebook credit nowadays. Dell and Amazon partner with Best Buy to sell computers and Kindle e-books respectively. There are interesting business opportunities for anyone who can funnel real customers and subscribers (read: money) into the virtual/communications world. Very real profits await those brick-and-mortar outfits who can build bridges between technology companies and customers, even if they are just plain-Jane grocery stores!

Wednesday, October 13, 2010

There has been a ton of research, standardization work, and development around Vertical Handover - the ability to change the underlying network access without disturbing the overlying communication protocol (TCP or application) sessions. The simplest example is when a user moves from a Wifi zone (e.g. office) to a 3G zone (outdoors). A seamless handover hides the underlying rewiring of the access and lets the user continue using the device as if nothing changed. Vertical handovers have quickly graduated from laboratory quirk to mainstream occurance, with Wifi-enabled smart-phones switching between access technologies multiple times daily.

But the vertical handover on my smart-phone doesn't really preserve the underlying TCP session and yet works pretty well. Why? Because most of the apps on my phone use REST-ful protocols like HTTP, XML-RPC, or SOAP. That means they are, in theory, stateless. In fact, a TCP connection is created and torn down for every message exchange between the service server and the client. Sometimes TCP connections linger on to improve efficiency (carrying multiple request-response mesages between the client and service server), but a discontinuity in the TCP connection is not catastrophic. I simply see my smart-phone negotiate a new connection with the new access (3G or Wifi) and then my app keeps working as if nothing has changed.

All that talk about preserving TCP connections across access technologies was much ado about nothing!

Wednesday, October 6, 2010

Tango is a newly launched mobile-to-mobile video calling application for iPhone and Android devices. Tango enables smart-phone owners to see each other in addition to speaking with each other during a Voice Over IP (voip) conversation. Many smart-phones come with front facing cameras, ostensibly for video calling, and Tango enables people to use these cameras during a voip call. Think of mobile video calling when you want to see your expat pet doing silly tricks on video (or for beach and boardroom voyeurism).

But, as Walter Mossberg's Tango's review in WSJ reports, the quality of Tango's video call leaves a lot to be desired. I came across a video on Gizmodo's website showing Tango in action. The verdict is that Tango's performance is way below expectation. In fact, Tango's video frame-rate seemed to be approximately 1 frame per second in the Gizmodo video (and not the "high quality video mobile calling service" as the company's press release claims).

Make no mistake, achieving even 1 frame-per-second video+voice is no small feat. Tango's engineers have packed a real-time video+voice encoder/decoder into a smart-phone and have managed to trasmit/receive two parallel audio/video streams over Wifi (they also claim high quality video calls over 3G but lets not give Tango all the benefit of doubt :-) ). On top of this, achieving this for both the Android and iPhone platforms and for dozens of smart-phone models is admirable.

Frankly, I am not surprised by Tango's dismal video frame rate - resource bottlenecks such as smart-phone hardware, software/OS, network bandwidth and latency have to be overcome before an acceptable double digit frame-rate is achieved. But what surprised me was the poor voice quality: the Tango call sounded a lot like those cheap international calling cards I used to make international calls from the US many years ago. Terrible sound quality. I wonder why Tango engineers didn't trade more video quality (or even cut out video entirely when resources were scarce) and spend resources on improving voice? Voice over IP for mobile phones is a solved problem - Skype and the umpteen number of mobile SIP voip clients got audio to work well even on older smart-phones. Why couldn't Tango?

Tango is an over-the-top application, meaning that it runs over the best-effort (ordinary) Internet. I mention this here because the alternative, 3G telecom-operator-supported video calling, uses a dedicated network channel to ensure call quality assurance. But a Tango call will be carried over the same pipes as plain web traffic, making the video/voice call quality dependent on what else is being transmitted during the call. Telecom-supported 3G video calling is also much more energy (battery) efficient than Tango.Why? Because in order to remain signed-into Tango to receive calls, the smart-phone has to periodically send "I-am-alive" messages to the Tango server. This means that a TCP or UDP socket is always active (or repeatedly created and and torn-down), effectively disabling the smart-phone's built-on power-saving sleep function. Offcourse, telecom supported 3G video calling costs money, but it is technically superior to Tango or any other over-the-top mobile video calling system.

But this is not about Telecom vs. Internet applications. This is about the use-case. Video calling was touted as one of the big use-cases for 3G Telecom networks (and 4G too?). 3G standards support video calling and so there is hardware acceleration, network resource reservation, optimized audio/video codecs, and cross-phone/OS support for video calling on every modern smart-phone. But apart from the cost of making 3G video calls, is their something else that relegated video calling to its sad never-used status in phones? Yes there is. Video calling has simply not been accepted as a viable form of mass communication in our society, and remains to-date, a quirky add-on. When was the last time you placed a video call?

When Internet telephony (voip) arrived it quickly replaced circuit-switched calling. With mobile video calling, even if Tango can eventually fix its technical/engineering limitations, there is nothing to replace! Sadly, the mobile video calling use-case was still-born from the beginning.